1. Technical Field
The present invention is broadly included in the technical field of ejecting a fluid from nozzle orifices. More particularly, the present invention relates to an inspective ejection method to be carried out on a fluid ejection apparatus to find any clogged nozzle orifice or nozzle orifices, and also to a fluid ejection apparatus implementing the inspective ejection method.
2. Related Art
Known ink jet printers as the fluid ejection apparatus eject ink droplets from nozzle orifices provided in a recording head module (ejection unit) so as to print on a target such as paper. When ink in the nozzle orifice thickens, the viscous ink residue clogs the nozzle orifice and disadvantageously leads to a blank ink dot due to failure of ejection.
WO00/29219 discloses a detection device for detecting such kind of blank ink dot (clogged nozzle orifice). This detection device determines that ink droplets are safely ejected when a leaser beam emitted from a light source is shielded by the ink droplets ejected from nozzle orifices. On the other hand, the device detects an ejection error (clogged nozzle orifice) caused by the viscous ink residue when the leaser beam is not shielded. When the ejection error is detected, the nozzle orifices of recording head modules are put under cleaning.
When a plurality of nozzle orifices are inspected, the inspection needs to be executed for each of the nozzle orifices one by one. The detection device disclosed in WO00/29219 is configured such that the inspection is executed while a relative position between the recording head module and the detection device continuously shifts so that the laser beam intersects with ink-droplets-ejection paths (ink-droplets-flight paths).
For instance, the recording head module has the plurality of (for example, 180) nozzle orifices arranged at a constant pitch, the nozzle orifices being arranged in arrays corresponding to associated ink colors. The nozzle orifices are marked with numbers, for example, #1 to #180. Firstly, positioning is conducted so that the ink-droplets-flight path of the nozzle orifice #1 intersects with an emission path of the laser beam, and then, ejection of the ink droplet is conducted so that clogging (blank dot) of the nozzle orifice #1, if any, is detected. By doing the same for all nozzle orifices #1 to #180 with shifting the number of nozzle orifices in turn, all the nozzle orifices #1 to #180 are inspected.
However, generating ejection data in the form of a dot pattern for the inspection, based on the ejection order of all the nozzle orifices #1 to #180, disadvantageously requires enormous storage capacity to store the generated ejection data in a memory (image buffer).